The present invention relates to a cellular telephone, and more specifically to a lighting circuit and antenna arrangement for a cellular telephone which enables the length of the coil of the antenna of the cellular telephone to be minimized without affecting its function.
A variety of cellular telephones have been developed, and have appeared on the market. A cellular telephone has an antenna for receiving and transmitting signal. In order to minimize the dimension of a cellular telephone, the length of the antenna (coil) must be limited. Further, the antenna of a cellular telephone may be mounted with a LED (light emitting diode), which emits light when the cellular telephone is in operation.
FIGS. 1 and 2 show a lighting circuit and antenna arrangement for a cellular telephone according to the prior art. As illustrated, a transparent cap 11 is covered on a receptacle 10. A post 12 is mounted inside the transparent cap 11 and connected to a connector 14 at the center of the receptacle 10. A coil 13 is mounted on the post 12 within the transparent cap 11. A downward extension rod 15 is extended from the connector 14 at the bottom and connected to the power supply circuit of the cellular telephone. A LED (light emitting diode) 16 is mounted on the post 12 at the top inside the transparent cap 11. The LED 16 has two legs, namely, the long leg 161 and the short leg 162 respectively connected to the coil 13. The long leg 161 of the LED 16 is inserted through an axially extended eccentric hole 17 in the post 12 and connected to a diode 163 in the eccentric hole 17, and then bent outwards and extended out of a side slot 18 on the post 12 and connected to a middle part of the coil 13. The short leg 162 of the LED 16 is bent outwards and connected to an upper part of the coil 13 above the post 12. By means of the impedance of the coil 13, the voltage is increased to turn on the LED 16, causing the LED 16 to emit light. Because the legs 161,162 of the LED 16 are respectively welded to the coil 13 at different elevations, the coil 13 must have a certain length L. Therefore, the antenna of the cellular telephone cannot be minimized. Furthermore, because the legs 161,162 of the LED 16 are directly welded to the coil 13 and driven by the impedance of the coil 13 to emit light, the installation of the LED 16 affects the signal receiving/transmitting operation of the coil 13.